If political and economic conditions particularly favorables for eleventh and twelfth centuries in the old diocese of Liege make the golden age of the Mosan art (the Meuse river valley), the hagiography is not outdone. Exceptional narrative sources instrumentalize the Mosan saints as powerful protectors in the space of an episcopal principality dependent on the the Holy Roman Empire. The working hypothesis is verified through the strict sense of hagiography : Triumphus sancti Remacli (c. 1071), Passio Agilolfi, Translatio Malmundarium and Miracula sancti Quirini et aliorum (after 1062), in a prolific author Sigebert of Gembloux, and in some scattered texts ((Vita Lamberti of canon Nicolas (c. 1145), relation of the pilgrimage Liege in Santiago ...).